A 36 year old gentleman presented to the Metabolic Bone Disease Clinic with a progressive history of thoracic and lower limb pain. He had originally been seen by the podiatrists with worsening foot pain for which no cause had been found. Initial investigation revealed a hypophosphataemic osteomalacia and a bone scan demonstrated multiple abnormalities suggesting old fractures.

Investigations were performed to establish the cause of the osteomalacia and we discuss the differential diagnosis and the progression towards a diagnosis based on the results of these tests. The most useful investigation in this case was an octreotide scan which indicated the presence of an endocrine tumour in the medial femoral condyle of the right knee.

Plain x-rays revealed no clear bony abnormality in the area of increased uptake on the octreotide scan. The lesion was therefore localised with an MRI scan.

This subsequently demonstrated the exact location of the lesion and in image guided biopsy was performed in theatre. This confirmed the presence of a benign Phosphaturic Mesenchymal tumour. This rare tumour is usually found in soft tissues and this case is atypical given that the lesion was wholly within the femoral condyle.

Despite the benign appearance of the tumour cells there were some areas of locally invasive growth and excision rather than curettage of the tumour was recommended. It was possible to preserve both the bulk of the femoral condyle and the articular surface although the knee was protected with a hinged brace for six weeks following surgery.

Follow up biochemistry results demonstrate that the serum phosphate and alkaline phosphatase are returning to normal. Symptomatically the patient is much improved.

Introduction: Large cysts of the proximal tibial metaphysis are an uncommon radiological finding amongst the elderly presenting to an arthroplasty clinic. We present two cases of such pathology in elderly patients. These were both associated with advanced degenerate disease in the knee.

In view of the size of the lesions these were both fully investigated with pre-operative radiology and an image guided biopsy. The first case was found to be a large degenerate myxoid cyst involving the majority of the tibial plateau. The second case appeared similar radiologically yet was a large metastasis from a bladder cancer. The only history offered by the after this had been established was that she had had a benign polyp removed some years previously.

Management: When dealing with unusual features of disease a cautious approach should be recommended. Both patients underwent staging investigations and biopsy prior to knee replacement surgery. In each case it was possible to graft the defect and using revision prostheses a good outcome has been achieved.

Conclusion: Large cysts appearing in association with degenerate disease of the knee are uncommon. Whilst these will often be related to the underlying arthritis this is not always the case and appropriate care should be taken to establish a diagnosis prior to surgery.

Introduction: The foot and ankle are common sites for benign tumours, ganglia and other conditions. The aim of this review was to look at the case mix requiring surgery that presented to a foot and ankle clinic over an eighteen month period.

Methods: Prospective data collection is performed for all patients presenting with lesions requiring surgery and this is stored on the tumour database in Oswestry.

Results: 80 cases presented over this period that required surgery.. There were 12 malignant primary tumours, 1 malignant metastasis, 5 cases of locally aggressive benign conditions (4 PVNS and 1 ABC) and the remaining 62 cases were benign conditions. There were more malignant conditions than there were ganglia.

Conclusions: In this series 16% of cases presenting as lumps to the foot and ankle clinic represented malignant disease. Although in most clinics this incidence will be diluted by other conditions of the foot and ankle, one must retain a high index of suspicion when dealing with lumps around the foot and ankle.